The present invention disclosed herein relates to a thermally curable resin composition for a protective film, including an alkoxy group-containing silane-modified epoxy resin as an essential component.
A color liquid crystal display device is treated with a solvent, an acid solution, or an alkali solution during preparation processes thereof, or the surface of the device is partially treated at a high temperature upon formation of a transparent electrode layer through a sputtering process. Occasionally, when the transparent electrode layer is etched to a desired shape, the above device is exposed to an acid solution or an alkali solution under severe conditions. In order to prevent damage to pixels due to heat or chemical material upon such treatment, a protective film, which consists of a thin film resistant to the above treatment, is provided.
Along with the trend of enlarging display devices such as liquid crystal displays (LCDs), the size of a substrate used is also being increasing. Accordingly, the color filter layer should be planarized, and the development of materials for a protective film for planarization of the color filter layer is essential in order to achieve a large area LCD.
Although compositions for a protective film are classified into a UV type using ultraviolet light and a thermally curable type according to the curing method, the thermally curable type is usually used because there is a limitation in performing UV irradiation with one shot according to an increase in the LCD area.
Since a composition for a protective film is coated entirely over a substrate unlike materials for color filters and is in contact with glass positioned outside the substrate, a color filter layer in the lower portion, and a column spacer in the upper portion or an ITO electrode, it is essential to secure adhesive strength between upper and lower layers.
In addition, although the strength of a protective film is also emerging as an important physical property due to increased LCD area, the development of a composition for a protective film, which may secure the strength of the protective film and the adhesive strength at the same time, is urgently needed because the two physical properties are inversely proportional to each other.